The present invention relates to a method of manufacturing a printed circuit board, particularly, to a method of manufacturing a printed circuit board comprising a step of forming a printed circuit on an insulating base board and a step of forming a circuit portion to be connected to the printed circuit by adhering a conductive ink on the printed circuit.
In the conventional printed circuit board, in order to form a necessary circuit, such as a jumper circuit or the like while connecting a portion of another circuit to a terminal portion of the printed circuit, a conductive ink such as a copper paste or a silver paste or the like, is printed or provided on an insulating base board and hardened, thereby forming the circuit portion.
In such a conventional printed circuit board, when the circuit portion, such as the jumper circuit or the like, is formed by applicating the conductive paste such as copper paste on the insulating base board or by a silk screen printing, a problem arises in adhesion properties between the conductive paste or ink and the circuit terminal portion of copper foil provided on the printed circuit board. That is, the resin ink of the conductive paste has a small adhesive force to the metal surface compared with the common resin ink, since a great amount of conductive materials, such as carbon particles, silver particles or copper particles are mixed in the resin ink in order to increase conductivity, so that the resin amount effect on the adhesive force to the terminal portion becomes small. This causes a pealing-off of conductive paste from the terminal portion by a thermal shock in case of soldering electrical components to the terminal portion.